Effects of nitrogen dioxide exposure on bronchoalveolar lavage proteins in humans

Nitrogen dioxide (NO2) is a pollutant of both outdoor and indoor atmospheres that has the potential to alter alveolar epithelial permeability. In order to assess alterations in the protein content of alveolar lining fluid induced by brief (3-h) exposures to low-level NO2, normal volunteers were exposed sequentially to air and NO2, separated by at least 2 wk, in an environmental chamber. Bronchoalveolar lavage (BAL) was performed after exposure. Four experimental protocols were used: (1) continuous 0.60 ppm NO2 with BAL performed 3.5 h after exposure (n = 8), (2) background 0.05 ppm NO2 with three 15-min peaks of 2.0 ppm followed by BAL 3.5 h after exposure (n = 15), (3) continuous 0.60 ppm NO2 with BAL performed 18 h after exposure (n = 8), and (4) continuous 1.5 ppm NO2 with BAL 3.5 h after exposure (n = 15). No changes in lavage fluid levels of total protein or albumin were observed in response to NO2. However, exposure to continuous 0.60 ppm NO2 was associated with increases in lavage fluid levels of the antiprotease alpha-2-macroglobulin (alpha 2M) when assessed 3.5 h after exposure (air versus NO2: 20 +/- 1 versus 29 +/- 2 ng/ml, P = 0.01). No significant changes in levels of alpha 2M in BAL fluid were observed in the other exposure protocols. Lavaged cell numbers, differential counts, and viability were not altered by exposure to the pollutant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of hyaluronic acid on the morphology and proliferation of human chondrocytes in primary cell culture.

Hyaline articular cartilage is a specialised connective tissue with weight bearing and adsorbing functions. Injury or loss of which often leads to impaired joint function and severe pain. Since the self-renewing abilities of hyaline articular cartilage are limited, there is major interest in the development of bioengineered cartilaginous implants. A cell-matrix-biocomposite composed of a collagen I/III scaffold seeded with autologous chondrocytes is currently being used in clinical trials; however, in order to optimise culture conditions, we cultured human condrocytes and seeded them on type I/III collagen membranes and on Thermanox plastic coverslips with media containing 0 to 500 microg/ml Hyaluronic Acid. After 4 days, the cells were either fixed or BrdU incorporation procedures begun. HE staining clearly demonstrated that cells grown in HA form three dimensional clusters and produce secretory vesicles as opposed to the monolayer control cells with noticeably fewer secretory vesicles. BrdU incorporation revealed a noticeable increase in cell proliferation in cells grown in 100 microg/ml; however, no comparable increase in 500 micorg/ml but rather a slight depression in proliferation. Immunohistochemistry for collagen II and aggrecan revealed an obvious increase in deposition of these two substances with increased HA administration as compared to the control; however, again, the higher concentration of HA, 500 microg/ml, did not result in a further increase in production. These results suggest that HA at 100 microg/ml not only influences chondrocytes to differentiate and produce more Collagen II and aggrecan, but also increases proliferation. We, therefore, propose that the addition of HA at low to middle dosages in condrocyte culturing might help improve condrocyte redifferentation and thus, the bioengineered cartilage.     

Histological changes of terminal bronchioles in rats during the exposure to nitrogen dioxide.

At long-term exposure to 5 ppm NO2 (w/w), courses of histological changes in the epithelium of the terminal bronchioles of rats were observed. In the course of the experiment the first alterative changes were expressed by the loss of cilia and cell differentiation. The changes were followed by epithelial hyperplasia, leading to conspicuous narrowing of the lumen of bronchioles. After the phase of hyperplasia a phase of reparation followed, leading to the development of nonciliated epithelium without determinable Clara cells, with areas of uniform multi-layered epithelium. At the same time, in the longest interval of 11 weeks new alterative changes analogous to those found at the beginning of the experiment were observed.     

Histogenesis of the papillary Clara cell adenoma.

The origin of the endocrine cells in the respiratory tract and the gastrointestinal tract is still a matter of debate. In the original concept of the amine precursor uptake and decarboxylation (APUD) system, all APUD cells were considered to be derived from the neural crest. More recently it has been proposed that the APUD cell types of the gastrointestinal and respiratory tracts originate from neuroendocrine-programmed ectoblast. Still other investigators have reported observations that favor a direct endodermal origin of these cell types. Based on the assumption that in teratomas different tissue types which in normal embryogenesis are derived from the neuroectoderm might be expected to occur together, we investigated a series of cystic ovarian teratomas and testicular teratocarcinomas for the presence of brain tissue and of different types of APUD cells. In the ovarian teratomas, intestinal and respiratory APUD cell types were found almost exclusively without coexistence of brain tissue, whereas melanocytes, which are of neuroectodermal origin, occurred mostly together with brain tissue. In the testicular teratocarcinomas, intestinal types of APUD cells occurred without brain tissue. Peptide hormone production was found in appropriate tissues. It can therefore be concluded that in teratomas appropriate intestinal and respiratory APUD cells differentiate in and presumably descend directly from intestinal and respiratory epithelium.     

Effects of benzodiazepines on thymus cell proliferation

The effects of three different benzodiazepine receptor ligands viz: diazepam, Ro 5-4864, and Ro 15-1788 on the mitotic activity of rat thymus were investigated. It was found that a single injection of diazepam resulted in a significant increase of the mitotic activity of the thymus cells 36 and 48 hours after drug administration. In contrast, Ro 5-4864 significantly depressed the mitotic activity rate 24 and 36 hours after injection. No significant change after the administration of Ro 15-1788 was found. These findings suggest the involvement of both central and peripheral benzodiazepine receptor in the control of thymus cell proliferation.     

Clara cell carcinoma of the lung

A peripheral scar adenocarcinoma of the lung was found to be composed of cells withthe ultrastructural features of Clara cells. It is suggested that malignant change occurred during hyperplastic and regenerative changes of the bronchiolar epithelium in which the Clara cell was the progenitor.     

Effects of chronic neonatal nicotine exposure on nicotinic acetylcholine receptor binding, cell death and morphology in hippocampus and cerebellum

Nicotine, the major psychoactive ingredient in tobacco interacting with nicotinic acetylcholine receptors (nAChR), is believed to have neuroprotective and neurotoxic effects on the developing brain. Neurotoxicity has been attributed to activation of homomeric alpha7 nAChRs, neuroprotection to heteromeric alpha4beta2 nAChRs. Thus, developmental nicotine could have opposite effects in different brain regions, depending on nAChR subtype expression. Here, we determined if chronic neonatal nicotine exposure (CNN), during a period of brain growth corresponding to the third human trimester, differentially regulates nAChR expression, cell death, and morphological properties in hippocampus and cerebellum, two structures maturing postnatally. Rat pups were orally treated with 6 mg/kg/day nicotine from postnatal day (P)1 to P7. On P8, expression for alpha4, alpha7 and beta2 mRNA was determined by in situ hybridization; nAChR binding sites by receptor autoradiography, dying neurons by TUNEL and Fluoro-Jade staining and morphological properties by analysis of Cresyl Violet-stained sections. In control cerebellum, strong expression of alpha4, beta2 mRNA and heteromeric nAChRs labeled with [125I]-epibatidine was found in granule cells, and alpha7 mRNA and homomeric nAChRs labeled with [125I]-alpha-bungarotoxin were in the external germinal layer. In control hippocampus, low expression of alpha4 mRNA and heteromeric nAChRs and high expression of alpha7 mRNA and homomeric nAChRs were detected. CNN increased heteromeric nAChR binding in hippocampus but not cerebellum and significantly decreased neuronal soma size and increased packing density in hippocampal principal cells but not in cerebellum. CNN did not increase the number of dying cells in any area, but significantly fewer TUNEL-labeled cells were found in CA3 strata oriens and radiatum and cerebellar granule layer. Thus, the hippocampus seems to be more sensitive than the cerebellum to CNN which could result from different nAChR subtype expression and might explain long-lasting altered cognitive functions correlated with gestational nicotine exposure due to changes in hippocampal cell morphology.     

Alcohol exposure inhibits adult neural stem cell proliferation

Alcohol exposure can reduce adult proliferation and/or neurogenesis, but its impact on the ultimate neurogenic precursors, neural stem cells (NSCs), has been poorly addressed. Accordingly, the impact of voluntary consumption of alcohol on NSCs in the subventricular zone (SVZ) of the lateral ventricle was examined in this study. The NSC population in adult male C57BL/6J mice was measured after voluntary alcohol exposure in a two-bottle choice task using the neurosphere assay, while the number of NSCs that had proliferated 2 weeks prior to tissue collection was indexed using bromodeoxyuridine (BrdU) retention. There was a significant decrease in the number of BrdU-retaining cells in alcohol-consuming mice compared with controls, but no difference in the number of neurosphere-forming cells that could be derived from the SVZ of alcohol-consuming mice compared with controls. Additionally, PCNA-labeled cells in the SVZ tended to be lower, but there was no difference in BrdU labeling in the dentate gyrus following alcohol exposure. To determine alcohol’s direct impact on NSCs and their progeny, neurospheres derived from naïve mice were treated with alcohol in vitro. Neurosphere formation was reduced by 100 mM alcohol without reducing cell viability. These findings are the first to assess the impact of moderate voluntary alcohol consumption on selective measures of adult NSCs and indicate that such exposure alters NSC proliferation dynamics in vivo and alcohol has direct but dissociable effects on the expansion and viability on NSCs and their progeny in vitro.     

TWEAK蛋白对肝癌细胞增殖的影响

目的 观察TWEAK蛋白对肝癌细胞系增殖的影响,探讨TWEAK对肝癌细胞增殖的作用.方法构建PAVU6-TWEAK siRNA干涉质粒,转染HepG2和QGY7703肝癌细胞株,MTT法检测抑制TWEAK蛋白表达对肝癌细胞增殖的影响,并于培养体系中加入TWEAK蛋白,检测肝癌细胞增殖活性.结果成功构建PAVU6-TWEAK siRNA干涉质粒,转化肝癌细胞后肝癌细胞增殖受抑.肝癌培养体系中加入TWEAK蛋白后,肝癌细胞增殖活性有所增强.结论 TWEAK蛋白可促进肝癌细胞的增殖活性,抑制TWEAK表达,一定程度上可抑制肝癌细胞增殖.     

Effects of interleukin-15 on in vitro human T cell proliferation and activation.

Interleukin-15 (IL-15) has been reported to have many activities on T cell populations, including a potential role in improving antigen-specific proliferation in HIV-1 disease. We tested this response in healthy adults by studying the response of T cell populations after stimulation with medium, tetanus, cytomegalovirus (CMV) antigens in cultures from 21 volunteers. IL-15 caused a dose-dependent increase in medium and antigen-induced proliferation. The expansion was due to CD8>natural killer (NK)>CD4 lymphocytes and memory > naive cells. The IL-15-stimulated CD8 cells had increased levels of the activation markers CD69 and DR. The published CMV-induced expression of CD57 on CD8+ cells was increased in CMV seronegative and seropositive subjects by IL-15. IL-15 appears to be a stimulator of T cell populations in healthy adults and may be useful in settings to enhance nonspecific NK activity or antigen-specific CD8 activity.     

重组人内抑素对人瘢痕疙瘩成纤维细胞形态及增殖的影响

目的 观察重组人内抑素(rhEndostatin)对体外培养的人瘢痕疙瘩成纤维细胞(KFs)增殖的影响。方法 体外培养及鉴定人KFs; 应用四甲基偶氮唑盐（MTT）法分别检测不同浓度rhEndostatin (6.25×10^-6、1.25×10^-5、2.50×10^-5、5.00×10^-5、1.00×10^-4mg/L)作用24h、48h、72h后对KFs增殖的影响,并同时观察其形态变化。结果 组织块接种7~8d后,其周边可见少许梭形细胞,继之细胞逐渐增多并以组织块为中心呈放射状生长;传2代培养的细胞单层排列,形态均一,呈长梭状,折光性好。细胞波形蛋白免疫化学染色显示胞质均呈棕黄色。rhEndostatin(6.25×10^-6 mg/L浓度组除外)能明显抑制KFs的增殖(P <0.05),抑制效应与rhEndostatin浓度和作用时间呈一定的依赖关系; 其中,5.00×10-⁵ mg/L 和1.00×10^-4 mg/L组rhEndostatin作用48 h后,细胞生长缓慢,体积变小,数目减少,排列紊乱。结论 重组人内抑素对人KFs增殖具有抑制作用。     

Effects of long-term testosterone exposure on ovarian function and morphology in the rhesus monkey

This study was aimed at developing a model in the rhesus monkey for the human gynecologic disorder termed the polycystic ovary syndrome (PCOS). The effects of chronic constant androgen exposure upon quantitative ovarian morphology and ovulatory function were examined. Twenty-five normally cycling females, aged 4-12 yr and weighing 3.3-8.2 kg, were enrolled in the study in random fashion. Seventeen animals were implanted subcutaneously (s.c.) with 10 or 25 mg testosterone-filled silastic tubing so as to maintain steady serum levels of testosterone averaging 80 ng/dl (low-dose group, n = 8) and 115 ng/dl (high-dose group, n = 9) for 13-16 months. Eight animals served as controls (sham implants); in these, mean serum testosterone levels averaged 24 ng/dl. No effect of androgen treatment was observed on ovulatory function as gauged by periodic luteal phase progesterone determinations and the presence of a fresh corpus luteum at laparoscopy. Menstrual cycle frequency (number of cycles over number of months of observation) was, however, slightly but significantly (P less than 0.05) reduced in the high-dose (88.9%) vs. the control (96.7%) and low-dose (95.0%) groups. Quantitative morphology, performed by light microscopy on a single ovary obtained from 16 of the 25 animals and read in a blinded fashion, revealed no differences in ovarian weight, capsular width and numbers, size, or proportion of healthy and atretic follicles among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of AFB1 embryonic exposure on chicken mononuclear phagocytic cell functions.

Effects of embryonic exposure to aflatoxin-B1 (AFB1) on the postnatal development of chicken mononuclear phagocytic system function was examined. Single exposure of 6-d chick embryos to 0.1, 0.5, and 1 micrograms AFB1 in 10 microL acetone was employed. Control embryos received 10 microliters solvent and sham-treated controls included embryos with a hole in the egg shell with no compound added. Aflatoxin B1 exposure caused a dose-related increase in embryonic mortality. After hatch, no differences were observed in body weight gain among treatment groups. The incidence of circulating thrombocytes was reduced in chicks exposed to the highest AFB1 dose with enhancement in monocyte and lymphocyte cell populations. Birds exposed to 1 microgram AFB1 recruited fewer macrophages in the peritoneal cavity after i.p. Sephadex elicitation along with reduced substrate adherence potential of peritoneal exudate cells. Similarly, macrophages from 0.5 and 1 micrograms AFB1-treated birds had depressed phagocytic potential. These results suggest that long-term immune depression of macrophage-mediated functions can occur following embryonic exposure to AFB1.     

Effects of formaldehyde gas on the respiratory tract of rhesus monkeys. Pathology and cell proliferation.

Formaldehyde is a nasal carcinogen in rats but it remains to be determined what cancer risk this chemical poses in humans. Molecular dosimetry studies of formaldehyde and cellular proliferative responses to formaldehyde-induced cytotoxicity have been studied in the rodent and are important components of the authors' ongoing research, which has now been extended to nonhuman primates, a species more analogous to humans. The present study was designed to characterize formaldehyde injury in the respiratory tract of nonhuman primates to provide a direct comparison to the toxic effects of formaldehyde in rodents. Groups of three rhesus monkeys were exposed to room air, or 6 ppm formaldehyde for 5 days per week for 1 or 6 weeks, and the respiratory tract was assessed for nature and extent of histologic responses, and changes in epithelial cell proliferation rate. Lesions were characterized by mild degeneration and early squamous metaplasia confined to specific regions of the transitional and respiratory epithelia of the nasal passages and the respiratory epithelium of the trachea and major bronchi. There was minimal progression of histologic changes between 1 and 6 weeks; however, the percent of nasal surface area affected significantly increased in the 6-week exposure group. Formaldehyde-induced lesions were associated with increases in cell proliferation rates up to 18-fold over controls, which remained significantly elevated after 6 weeks of exposure. Histologic lesions and increases in cell proliferation were most extensive in the nasal passages and were minimal in the lower airways, whereas the maxillary sinuses exhibited no evidence of a response to formaldehyde exposure. Based on the extent of lesions and cell proliferation data, it appears that the monkey is more sensitive than the rat to the acute and subacute effects of formaldehyde at 6 ppm. The absence of response in the maxillary sinuses in the monkey suggests that combining tumors of the nasal cavity and sinuses in epidemiologic studies may not be appropriate for formaldehyde cancer risk assessment. Results of this study also have provided important information for tissue sample site selection in the monkey respiratory tract for ongoing molecular dosimetry studies.     

2,3,7,8-四氯苯二噁英宫内暴露对子鼠肾细胞及其亚细胞结构的毒性影响

目的 探讨妊娠早期母鼠接触2,3,7,8-四氯苯二噁英(TCDD)后对子代新生鼠肾的毒性影响.方法 妊娠13d的SD雌性大鼠随机分为对照组、玉米油组和染毒组(每组6只),观察3组大鼠出生3d雌性鼠的肾细胞及其亚细胞结构差异.结果 对照组子鼠和玉米油组子鼠的肾,不论是细胞结构还是亚细胞结构均未见病理改变.染毒组中,5 n...